“I am obliged to you, sir,” said Zorzi coldly.  “I shall not need to disturb you.”

“You are not wise,” returned Giovanni gravely.  “If I were curious—­fortunately for you I am not!—­I would send for a mason and have some of the stones of the pavement turned over before me.  A mason would soon find the one you moved by trying them all with his hammer.”

“Yes,” said Zorzi.  “If this were a room in your own glass-house, you could do that.  But it is not.”

“I am in charge of all that belongs to my father, during his absence,” answered Giovanni.

“Yes,” said Zorzi again.  “Including Paolo Godi’s manuscript, as you told me,” he added.

“You understand very well why I said that,” Giovanni answered, with visible annoyance.

“I only know that you said it,” was the retort.  “And as I cannot suppose that you did not know what you were saying, still less that you intentionally told an untruth, I really cannot see why you should suggest bringing a mason here to search for what must be in your own keeping.”

Zorzi spoke with a quiet smile, for he felt that he had the best of it.  Be was surprised when Giovanni broke into a peal of rather affected laughter.

“You are hard to catch!” he cried, and laughed again.  “You did not really suppose that I was in earnest?  Why, every one knows that you have the manuscript here.”

“Then I suppose you spoke ironically,” suggested Zorzi.

“Of course, of course!  A mere jest!  If I had known that you would take it so literally—­” he stopped short.

“Pray excuse me, sir.  It is the first time I have ever heard you say anything playful.”

“Indeed!  The fact is, my dear Zorzi, I never knew you well enough to jest with you, till to-day.  Paolo Godi’s secrets in my keeping?  I wish they were!  Oh, not that anything would induce me to break the seals.  I told you that.  But I wish they were in my possession.  I tell you, I would pay down half my fortune to have them, for they would bring me back four times as much within the year.  Half my fortune!  And I am not poor, Zorzi.”

“Half your fortune?” repeated Zorzi.  “That is a large sum, I imagine.  Pray, sir, how much might half your fortune be, in round numbers?  Ten thousand silver lires?”

“Silver!” sneered Giovanni contemptuously.

“Gold, then?” suggested Zorzi, drawing him on.

“Gold?  Well—­possibly,” admitted Giovanni with caution.  “But of course I was exaggerating.  Ten thousand gold pounds would be too much, of course.  Say, five thousand.”

“I thought you were richer than that,” said Zorzi coolly.

“Do you mean that five thousand would not be enough to pay for the manuscript?” asked Giovanni.

“The profits of glass-making are very large when one possesses a valuable secret,” said Zorzi.  “Five thousand—­” He paused, as though in doubt, or as if making a mental calculation.  Giovanni fell into the trap.